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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 5:30 pm

YYZatcboy wrote:
I can't find this story on the AFP website, and all of the websites I can find searching the first paragraph I've never heard of. If anyone can find a link to the actual wire story or a reputable news site publishing it as well I'd love to see a link.

A few reprints are showing up on Google, all pointing back to the same AFP story, but no second source.

Also two stories that seem to be written by AFP that are about the MAX tragedy but do not make the same claims have posted early today Paris time:

Seems like the controversial story got yanked.

Maybe they got the story wrong, or maybe they got pressured to yank the story?

This should be great for our conspiracy theory fans.
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WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 5:57 pm

YYZatcboy wrote:
I can't find this story on the AFP website, and all of the websites I can find searching the first paragraph I've never heard of. If anyone can find a link to the actual wire story or a reputable news site publishing it as well I'd love to see a link.


France24 has the exact same text:
https://www.france24.com/en/20190804-be ... ny-culture
and credits "AFP 2019" as source.

Been spread quite a bit:
https://www.google.com/search?q=%22The+ ... 2&safe=off
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MrBretz
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 6:07 pm

oOfredOo wrote:
Thorkel wrote:
MrBretz wrote:
Thorkel, thanks for the VxWorks overview. What’s your guess on an OS for the computers aboard the MAX?


I personally doubt there is one.



I concur. This website lists the Boeing 737 software as written in Ada. https://www2.seas.gwu.edu/~mfeldman/ada ... mmary.html
If it's correct, at least we know the programming language.


I wonder if you can write something in Ada that takes over the machine? I am thinking of writing an “executable image” with a scheduler on top, calling all the real time jobs periodically. In other words, supplanting the OS as many of us see it. But all written in Ada so it is understandable and has calls out to industry standard stuff. It sounds reasonable to me. My only experience in Ada is taking a course years and years ago, I.e., no real experience.

To all you software types, thanks.

Now we can get back to the real issues like MCAS, the 737 never flying again, and Boeing going bankrupt.
 
XRAYretired
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 6:33 pm

WIederling wrote:
YYZatcboy wrote:
I can't find this story on the AFP website, and all of the websites I can find searching the first paragraph I've never heard of. If anyone can find a link to the actual wire story or a reputable news site publishing it as well I'd love to see a link.


France24 has the exact same text:
https://www.france24.com/en/20190804-be ... ny-culture
and credits "AFP 2019" as source.

Been spread quite a bit:
https://www.google.com/search?q=%22The+ ... 2&safe=off

MSN, YAHOO and reddit all carry it verbatim. Credit on several is Luc Olinga - AFP. If its a spoof, its been a good un.

Ray
 
MNS45724
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 7:57 pm

The belief that Boeing is too big to fail reminds me of the once held belief that the RMS Titanic was too solid to sink. History teach us that it wasn’t despite what many people - most of which were British - believed before it left Southampton on its maiden voyage to New York City. Tragically, its last. Before I go on with the main argument of this post, I would like to underline, and I would do so ten times if this editor would allow me, that I truly hope that Boeing survives this huge mess it put itself into. Yes, I am European and yes, I’m happy if Airbus - which is far from being a perfect company - sales a few more passenger aircrafts a year than Boeing. However, I am first of all a civil aviation enthusiast which loves to see as much variety of metal birds as possible in the air and on the ground. Thus, the parallel between Boeing and the RMS Titanic which I made at te beginning of the post, really worries me. We have lost already to many giants in the aviation world. Boeing has made a huge mess of the two new commercial project developed after the 777. The 787 is now an amazing airplane but the amount of excess money Boeing wasted to bring it to the excellent level of maturity it is today is insane. Moreover, the time lost on the development schedule gave Airbus the opportunity, without losing too much ground over its rival, to develop a decent competitor to the 787, the A330neo, and an excellent new product just above that segment of the market, the A350. No matter haw Boeing’s accounting books work, the truth of the matter is that the billions of us dollars burned by the company to rectify the initial mess with the 787 are lost for good. Money which Boeing needed to successfully achieve the development of 737 MAX and, at the same time, make a profit and pay large dividends to its shareholders. If we look at the high dividend paid by Company in recent years, at the huge profit it made in the same period with their commercial aircraft division and at to the dismal state of the MAX project right now, it is quite evident where the US Manufacture decided cut corners. Nobody can deny, I think, that a company, no matter its size, Iva the ability to come out from a badly mismanaged project like the 787 without major bruises. The 737MAX debacle, if it is not ratified soon, will bring many more and much stronger shock waves to Boeings' accounting books than the 787 initial failures. We are looking to broken bones and not bruises only ... in my opinion. The development of the amazing MOM might suffer the same shortage of money than effected its predecessor. If Boeing doesn’t pull its acts together and if it doesn't set for itself the right financial priorities before it embarks on its next project I would not be surprised to see it go into cardiac arrest if it mess that up too. Insormontabile situations start always from small problems which become progressively larger if ignored. Denial of the existence of these problems is often the cause of their unstoppable expansion. Nothing on earth is to big or complex to fail. If there are the right condition they will Now Boeing must learn from its past mistake and rectify its unhealthy way of doing business to ensure its survival in future before it's too late ... I don’t want to see history repeating itself. I want Boeing to return to its former glory. I don’t want it to sink. My fav planes are the 727, 747 classics and the 757.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 9:06 pm

MrBretz wrote:
I concur. This website lists the Boeing 737 software as written in Ada. https://www2.seas.gwu.edu/~mfeldman/ada ... mmary.html
If it's correct, at least we know the programming language.

Hmm, it lists 737-200 which first rolled out on June 29, 1967 as using Ada which was first proposed in 1977, first standardized in 1980 and first validated in 1983.
Ref: https://en.wikipedia.org/wiki/Boeing_737#737-200
Ref: https://en.wikipedia.org/wiki/Ada_(programming_language)#History

Earlier in this thread it was posted that the 737 FCC is based on 290x bit slice processors implementing a 16 bit microprocessor, but the 290x didn't appear till 1975.

The 737 Classics first flew in 1984 which allows for 290x and also allows for 80286 which at least one source suggests is the basis of the FCC.

We need better references, or someone to go to the scrapyard and take apart a 737 FCC.

MrBretz wrote:
Now we can get back to the real issues like MCAS, the 737 never flying again, and Boeing going bankrupt.

I thought you had a pretty good list, but it seems we both neglected to include comparing the 737 to the Titanic.
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MrBretz
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 9:19 pm

Revelation, I have to fly up to SEA in a couple of weeks. Maybe I will have my ears open and see if any Boeing software developers are on the plane and we can get to the bottom of the software mystery. I do know that on the ancient military aircraft I worked on, they did swap out the flight computers later in the planes life. They did a rewrite, or as I recall, more like a conversion. I recall getting a call from a cohort I hadn't heard from in years asking me about some logic in something I wrote. But I can't remember when that was. So there is chance the older aircraft may have had new software in newer computers and it may have been converted as opposed to rewritten or redesigned.

Now back to the important stuff. Yes, I forgot to throw in the Titanic. Glad you mentioned it.
 
packsonflight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 9:48 pm

https://www.seattletimes.com/business/b ... -controls/

I am wondering what this means actually... Now Boeing is fundamentally redesigning the MAX flight control system because FAA discovered some "esoteric and remote" condition in the FCC computers, so is Boeing redesigning the whole thing for no particular reason, or has the real problem with the flight control system bin discovered, and that is the real reason for the redesign?

Is it realistic to pull a readisgin like that out of a hat in few weeks (ready by the end of sept according to Boeing) and how long time is the certification going to take, because for a redisign like that grandfathering rules do not apply.
 
packsonflight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 10:17 pm

https://www.satcom.guru/2019/07/movable-stabilizer.html

Excellent article by Peter Lemme. It describes the stall characteristics of airliners, and the certifacation rules that apply.

Apparently the MAX is unstable aircraft without MCAS. It is not unstable as modern fighters are, but one can argue that stall characteristics of the MAX renders it un certifiable according to FAR 25 certification standards, but with MCAS working it meets the criteria.

So how is it possible to certify the MAX and not having to demonstrate stall behaviour with MCAS off?
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 10:25 pm

packsonflight wrote:
https://www.seattletimes.com/business/boeing-aerospace/newly-stringent-faa-tests-spur-a-fundamental-software-redesign-of-737-max-flight-controls/

I am wondering what this means actually... Now Boeing is fundamentally redesigning the MAX flight control system because FAA discovered some "esoteric and remote" condition in the FCC computers, so is Boeing redesigning the whole thing for no particular reason, or has the real problem with the flight control system bin discovered, and that is the real reason for the redesign?

Is it realistic to pull a readisgin like that out of a hat in few weeks (ready by the end of sept according to Boeing) and how long time is the certification going to take, because for a redisign like that grandfathering rules do not apply.

ST is using some pretty sensational language, as the media is wont to do.

The changes they describe do NOT amount to "redesigning the whole thing".

They amount to keeping both flight control computers active at the same time (right now one is active and the other is standby), comparing their outputs, and if they differ in a meaningful way, the automated flight mode is terminated and manual mode is entered, with appropriate crew alerts.

This is a new mode of operation, and a change in the software architecture, and perhaps could be viewed as a redesign, since the original design did not keep both computers active at the same time, and requires a lot of testing, but is definitely not "redesigning the whole thing". Almost everything will stay the same except for the addition of the comparison logic and the reversion to manual mode.

As the article suggests, Boeing could have taken the easy way out and made some "point fixes" to get past the issue the FAA raised, but decided to do a more robust solution that solves pretty much any/all bit flip issues.
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planewasted
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 10:30 pm

RickNRoll wrote:
RickNRoll wrote:
This isn't good. Boeing knew about MCAS risk before the crashes.

NEW YORK: 

Even before the Lion Air and Ethiopian Airlines crashes claimed 346 lives, Boeing flight tests had revealed problems similar to those encountered by pilots on the ill-fated 737 MAX flights.

Company officials learned that its MCAS anti-stall system -- which is at the center of both accidents -- activated within minutes of takeoff, repeatedly pushing the nose of the aircraft down even when the plane was operating in normal conditions at lower speed.

This discovery, recounted to news agency AFP by two former Boeing engineers who spoke on the condition of anonymity, suggested that mastering the MCAS was important for safely flying the MAX.

The MCAS should have been closely vetted by regulators, and procedures for operating the system should have been included in plane manuals and highlighted during pilot training.

But none of that happened.



Story to be confirmed but devastating if true.
https://www.ndtv.com/world-news/behind- ... re-2080007


AFP is the source for this story so it sounds legitimate. Boeing knew that MCAS was deadly before any crashes occurred. This wasn't a matter of failing to explore all the failure modes or similar mistakes. This was a cover up.


Hmm... Wonder if Boeing knew the dangers of MCAS and did the ugly hack of disabling it if flaps are not retracted? Because with flaps retracted the plane is likely at such a high altitude that it should be 'easy' to survive an uncommanded stabilizer movement..?
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 10:35 pm

packsonflight wrote:
https://www.satcom.guru/2019/07/movable-stabilizer.html

Excellent article by Peter Lemme. It describes the stall characteristics of airliners, and the certifacation rules that apply.

Apparently the MAX is unstable aircraft without MCAS. It is not unstable as modern fighters are, but one can argue that stall characteristics of the MAX renders it un certifiable according to FAR 25 certification standards, but with MCAS working it meets the criteria.

So how is it possible to certify the MAX and not having to demonstrate stall behaviour with MCAS off?

The article you cite does not say the 737 MAX is unstable.

Please provide a suitable reference or clarify your post.
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f1restate
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 10:56 pm

There is something that is bugging me. Is this FCC redundancy which is going to be implemented, just because of the cosmic ray bit flipping issue? We are talking extremely low probabilities here , are we not ? Arranging 5 bits in this particular order surely has to be an event more than 6 sigmas away.
I am far from the conspiracy type, however it does feel like something else is at play here.

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IADFCO
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 11:30 pm

packsonflight wrote:
https://www.satcom.guru/2019/07/movable-stabilizer.html

Excellent article by Peter Lemme. It describes the stall characteristics of airliners, and the certifacation rules that apply.

Apparently the MAX is unstable aircraft without MCAS. It is not unstable as modern fighters are, but one can argue that stall characteristics of the MAX renders it un certifiable according to FAR 25 certification standards, but with MCAS working it meets the criteria.

So how is it possible to certify the MAX and not having to demonstrate stall behaviour with MCAS off?


Yes, the article is an interesting qualitative discussion of stall characteristics. I still don't quite understand the reason for the "stick lightening," though. The usual answer so far has been that the nacelle generates lift at a sufficiently high angle of attack, and that lift generates the extra pitching moment that the pilot does not have to generate through the stick (hence, stick lightening).

However, the nacelle is an annular airfoil, and annular airfoils tend to stall relatively late, so the CL(alpha) relationship is basically linear through the stall angle of the isolated wing and beyond (depending on the internal "airfoil like" shape of the nacelle). In other words, if this applies to the MAX as well, the nacelle lift would decrease the slope of the Cm(alpha) curve, but by the same amount for all alphas through stall and beyond, and would not cause the change in slope that we call "stick lightening".

If the NG complies with FAA regulations about the linearity of the force-alpha curve, and if (repeat, if) the nacelle has a linear behavior too, then it might be something related to something new introduced by the coupling of the engine and the wing, such as different patterns of flow separation induced by having this big engine basically in front of the leading edge of the wing. Identifying true reason for the stick lightening might be academic, but it might also have an impact of what MCAS is supposed to do.

There was a discussion on this general area in the Tecnical forum a few months ago, but it stopped before it got to this point.
 
packsonflight
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Sun Aug 04, 2019 11:34 pm

Revelation wrote:
packsonflight wrote:
https://www.satcom.guru/2019/07/movable-stabilizer.html

Excellent article by Peter Lemme. It describes the stall characteristics of airliners, and the certifacation rules that apply.

Apparently the MAX is unstable aircraft without MCAS. It is not unstable as modern fighters are, but one can argue that stall characteristics of the MAX renders it un certifiable according to FAR 25 certification standards, but with MCAS working it meets the criteria.

So how is it possible to certify the MAX and not having to demonstrate stall behaviour with MCAS off?

The article you cite does not say the 737 MAX is unstable.

Please provide a suitable reference or clarify your post.


The article does not mention MAX as I recall, but it describes acceptable stall behaviour of FAR 25 aircraf,t and as I understand the MAX without MCAS does not meet the criteria, otherwise the system would not be designed in the fist place.

FBW aircrafts have envelope protection in normal mode, but I believe FAR 25 stall behaviour still have to be met in direct mode, without all the gimmick.
the question remains, how can Boeing get away with certifying MAX stall behaviour wihtout MCAS working
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:31 am

IADFCO wrote:
I still don't quite understand the reason for the "stick lightening," though


I believe the issue has to do with an FAR specifying that in certain situations stick forces must increase with increasing airspeed, something like 1 lb per 6 kts increase or something like that. The MAX apparently doesn't meet this criteria in certain parts of its envelope without some help (MCAS or something that accomplishes the same thing).
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RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:44 am

XRAYretired wrote:
WIederling wrote:
YYZatcboy wrote:
I can't find this story on the AFP website, and all of the websites I can find searching the first paragraph I've never heard of. If anyone can find a link to the actual wire story or a reputable news site publishing it as well I'd love to see a link.


France24 has the exact same text:
https://www.france24.com/en/20190804-be ... ny-culture
and credits "AFP 2019" as source.

Been spread quite a bit:
https://www.google.com/search?q=%22The+ ... 2&safe=off

MSN, YAHOO and reddit all carry it verbatim. Credit on several is Luc Olinga - AFP. If its a spoof, its been a good un.

Ray


It appears to have disappeared. It was on the AFP web site in French but not English. That has gone too now.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:48 am

packsonflight wrote:
Revelation wrote:
packsonflight wrote:
https://www.satcom.guru/2019/07/movable-stabilizer.html

Excellent article by Peter Lemme. It describes the stall characteristics of airliners, and the certifacation rules that apply.

Apparently the MAX is unstable aircraft without MCAS. It is not unstable as modern fighters are, but one can argue that stall characteristics of the MAX renders it un certifiable according to FAR 25 certification standards, but with MCAS working it meets the criteria.

So how is it possible to certify the MAX and not having to demonstrate stall behaviour with MCAS off?

The article you cite does not say the 737 MAX is unstable.

Please provide a suitable reference or clarify your post.


The article does not mention MAX as I recall, but it describes acceptable stall behaviour of FAR 25 aircraf,t and as I understand the MAX without MCAS does not meet the criteria, otherwise the system would not be designed in the fist place.

FBW aircrafts have envelope protection in normal mode, but I believe FAR 25 stall behaviour still have to be met in direct mode, without all the gimmick.
the question remains, how can Boeing get away with certifying MAX stall behaviour wihtout MCAS working


Even in direct mode, the relationship between force applied to the controls and control surface movement is handled by the FCC. If the MAX was FBW, MCAS would be a simple force feedback algorithm for artificial feel. The "gimmick" would still be there but they wouldn't have to change the trim.

I still haven't seen an explanation about why they couldn't fix the issue with the elevator feel computer instead of MCAS. My assumption is that there was no easy way to feed AoA readings into the EFC.
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 2:15 am

packsonflight wrote:
https://www.seattletimes.com/business/boeing-aerospace/newly-stringent-faa-tests-spur-a-fundamental-software-redesign-of-737-max-flight-controls/

I am wondering what this means actually... Now Boeing is fundamentally redesigning the MAX flight control system because FAA discovered some "esoteric and remote" condition in the FCC computers, so is Boeing redesigning the whole thing for no particular reason, or has the real problem with the flight control system bin discovered, and that is the real reason for the redesign?

Is it realistic to pull a readisgin like that out of a hat in few weeks (ready by the end of sept according to Boeing) and how long time is the certification going to take, because for a redisign like that grandfathering rules do not apply.

To me that sounds strange.

I completely agree that time frame for such rework is entirely unrealistic. But more importantly, I'm not buying the premise that FAA mandated a massive rework of software at 11th hour, for such ridiculously improbable event. I mean, 5 specific bits, flipped all at the same time. And that Boeing swallowed it. It just does not make sense. I know FAA is in a position where they need demonstrate they are being diligent, but that is reaching the level of absurdity. This whole rework, done in a hurry, will only make things worse.

They could've made Boeing fix the rudder cables vulnerability. At least that would've made sense.

It is also worth noting in this story that there is no official word from Boeing about the nature of the problem, and what steps they are taking to rectify it. No word from FAA either. Now I can see why FAA is being quiet, but Boeing? It is like they (Boeing) are deliberately leaking some nonsense that portrays the new issue as "remote and esoteric". But I do not accept that FAA would insists on fixing "remote and esoteric" thing.

Bottom line, I believe the real problem is more serious that these sources make it look.
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 3:01 am

ArgentoSystems wrote:
packsonflight wrote:
https://www.seattletimes.com/business/boeing-aerospace/newly-stringent-faa-tests-spur-a-fundamental-software-redesign-of-737-max-flight-controls/

I am wondering what this means actually... Now Boeing is fundamentally redesigning the MAX flight control system because FAA discovered some "esoteric and remote" condition in the FCC computers, so is Boeing redesigning the whole thing for no particular reason, or has the real problem with the flight control system bin discovered, and that is the real reason for the redesign?

Is it realistic to pull a readisgin like that out of a hat in few weeks (ready by the end of sept according to Boeing) and how long time is the certification going to take, because for a redisign like that grandfathering rules do not apply.

To me that sounds strange.

I completely agree that time frame for such rework is entirely unrealistic. But more importantly, I'm not buying the premise that FAA mandated a massive rework of software at 11th hour, for such ridiculously improbable event. I mean, 5 specific bits, flipped all at the same time. And that Boeing swallowed it. It just does not make sense. I know FAA is in a position where they need demonstrate they are being diligent, but that is reaching the level of absurdity. This whole rework, done in a hurry, will only make things worse.

They could've made Boeing fix the rudder cables vulnerability. At least that would've made sense.


Boeing made the spoilers FBW. A smaller task perhaps but it shows what can be done.
 
ArgentoSystems
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 3:10 am

RickNRoll wrote:
Boeing made the spoilers FBW. A smaller task perhaps but it shows what can be done.


Did they do it in 3 months?
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 3:10 am

RickNRoll wrote:
ArgentoSystems wrote:
packsonflight wrote:
https://www.seattletimes.com/business/boeing-aerospace/newly-stringent-faa-tests-spur-a-fundamental-software-redesign-of-737-max-flight-controls/

I am wondering what this means actually... Now Boeing is fundamentally redesigning the MAX flight control system because FAA discovered some "esoteric and remote" condition in the FCC computers, so is Boeing redesigning the whole thing for no particular reason, or has the real problem with the flight control system bin discovered, and that is the real reason for the redesign?

Is it realistic to pull a readisgin like that out of a hat in few weeks (ready by the end of sept according to Boeing) and how long time is the certification going to take, because for a redisign like that grandfathering rules do not apply.

To me that sounds strange.

I completely agree that time frame for such rework is entirely unrealistic. But more importantly, I'm not buying the premise that FAA mandated a massive rework of software at 11th hour, for such ridiculously improbable event. I mean, 5 specific bits, flipped all at the same time. And that Boeing swallowed it. It just does not make sense. I know FAA is in a position where they need demonstrate they are being diligent, but that is reaching the level of absurdity. This whole rework, done in a hurry, will only make things worse.

They could've made Boeing fix the rudder cables vulnerability. At least that would've made sense.


Boeing made the spoilers FBW. A smaller task perhaps but it shows what can be done.


Spoilers are much easier. Doing the rudder would need a force feedback/artificial feel system added for the pedals.

I think based on Mentour Pilot video that they also changed the landing gear to extend/retract by wire.
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 3:14 am

packsonflight wrote:
https://www.satcom.guru/2019/07/movable-stabilizer.html

Excellent article by Peter Lemme. It describes the stall characteristics of airliners, and the certifacation rules that apply.

Apparently the MAX is unstable aircraft without MCAS. It is not unstable as modern fighters are, but one can argue that stall characteristics of the MAX renders it un certifiable according to FAR 25 certification standards, but with MCAS working it meets the criteria.

So how is it possible to certify the MAX and not having to demonstrate stall behaviour with MCAS off?

Even though the article doesn't support what you say regarding instability, it at least explains why there are two stab trim cutout switches. Also explains that the NG, not the MAX is to blame for having to turn off all electric trim or have both automatic and manual operating.
 
WIederling
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 7:54 am

RickNRoll wrote:
It appears to have disappeared. It was on the AFP web site in French but not English. That has gone too now.


Written by Luc Olinga and taken up by a range of sites:
https://muckrack.com/luc-olinga/articles
Look for Title:
"Behind the MAX crisis: Lax regulator, top-down company culture"

sent an info request to AFP. Lets what is returned.
Murphy is an optimist
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 8:07 am

oOfredOo wrote:
Thorkel wrote:
MrBretz wrote:
Thorkel, thanks for the VxWorks overview. What’s your guess on an OS for the computers aboard the MAX?


I personally doubt there is one.



I concur. This website lists the Boeing 737 software as written in Ada. https://www2.seas.gwu.edu/~mfeldman/ada ... mmary.html
If it's correct, at least we know the programming language.


There will be an OS and an AS. AS containing all the things that interface with the airframe.


If that website is accurate, and the 737 is using Ada, then I assume the electronics were completely re-done for the NG...?
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 8:24 am

Revelation wrote:
packsonflight wrote:
https://www.seattletimes.com/business/boeing-aerospace/newly-stringent-faa-tests-spur-a-fundamental-software-redesign-of-737-max-flight-controls/

I am wondering what this means actually... Now Boeing is fundamentally redesigning the MAX flight control system because FAA discovered some "esoteric and remote" condition in the FCC computers, so is Boeing redesigning the whole thing for no particular reason, or has the real problem with the flight control system bin discovered, and that is the real reason for the redesign?

The changes they describe do NOT amount to "redesigning the whole thing".

They amount to keeping both flight control computers active at the same time (right now one is active and the other is standby), comparing their outputs, and if they differ in a meaningful way, the automated flight mode is terminated and manual mode is entered, with appropriate crew alerts.


Ugh that is bad. Really bad. If Boeing had a shortcut, they would have taken it - or the report isn't entirely accurate as to the scope of the changes.


I agree that it is not redesigning "the whole thing" - but if they have to make both channels operate simultaneously throughout operation it is a very deep redesign of the fundamentals of operation.

An awful lot of assumptions for operation may have gone out the window and require significant rejigging of operations. Do they even have inter-channel comms set up already? Can the hardware take on that processing and memory burden?

Its (usually) not enough to just compare the final outputs and go "ah, this is bad, turn it all off" - instead you have to be able to identify root sources of inconsistency and have appropriate measures to at least present pertinent information to the pilots (if not automatically compensate and continue).


If that dual channel operation is not limited to MCAS alone, but instead is anything approaching the entirety of FCC capabilities, then airlines can completely forget about 2019 return to service. It'll be 12 months minimum from when the work started - they simply won't have enough people available that understand the architecture deeply enough to go any quicker and keep it safe. If significant chunks of the FCC OS and AS are being re-architected then I'm not even sure I'd see a 2020 return to service as realistic either.
 
FluidFlow
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 8:38 am

Will dual channel input lead to new sim training as there are new failure modes in this configuration?
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 8:48 am

FluidFlow wrote:
Will dual channel input lead to new sim training as there are new failure modes in this configuration?


Good question and one I never considered.

To avoid training changes, the whole thing would have to operate autonomously in the background - which places a much bigger burden on the FCCs in terms of problem diagnosis and taking correct remedial action.

Otherwise, the pilots would have to be trained to deal with the new notifications and whatever limitations the source issues impose on FCC operation.


If Boeing are seriously going to attempt to (significantly) redo the FCC without requiring any additional pilot training, then forget about return to service in 2020!


[Of course, I note again, the reporting could be wrong in terms of scope of changes.]
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 9:00 am

Oh and:

Boeing could have just rewritten the software governing what functions are monitored within the flight-control computer to eliminate this failure scenario.

Instead, it’s decided to make a much more radical software redesign, one that will not only fix this problem but make the MAX’s entire flight-control system — including MCAS — more reliable, according to three sources.


Chances are Boeing couldn't do the former due to H/W limitations, so instead have to go through a more tortuous S/W alternative.
 
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flyingphil
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 10:56 am

I have been wondering about this myself..

“346 People Have Died on Boeing’s Newest Jet. Why the Hell Does the CEO Still Have a Job?”
https://www.thedailybeast.com/why-the-h ... ax-scandal

A change in leadership is overdue at Boeing
https://www.theglobeandmail.com/busines ... at-boeing/

no let up in the bad news for Boeing ;(

https://www.postandcourier.com/business ... d055e.html
 
RickNRoll
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 11:18 am

Amiga500 wrote:
Oh and:

Boeing could have just rewritten the software governing what functions are monitored within the flight-control computer to eliminate this failure scenario.

Instead, it’s decided to make a much more radical software redesign, one that will not only fix this problem but make the MAX’s entire flight-control system — including MCAS — more reliable, according to three sources.


Chances are Boeing couldn't do the former due to H/W limitations, so instead have to go through a more tortuous S/W alternative.


It could just be that decades of hacks and patches really needed to be rewritten formally.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 11:38 am

Amiga500 wrote:
If that dual channel operation is not limited to MCAS alone, but instead is anything approaching the entirety of FCC capabilities, then airlines can completely forget about 2019 return to service. It'll be 12 months minimum from when the work started - they simply won't have enough people available that understand the architecture deeply enough to go any quicker and keep it safe. If significant chunks of the FCC OS and AS are being re-architected then I'm not even sure I'd see a 2020 return to service as realistic either.

Yet the same media reports describing the design/architecture changes references Boeing sources saying they expect to submit their changes in September and hope for approval in October.

Also, reports from the quarterly results call gave the same dates and explicitly included the fix for the "microprocessor issue".

Sure, it could be another overly optimistic date from Boeing, but the thing is, none of us know when the work on the design/architecture change started.

Some content posted around the time the "microprocessor issue" was first raised suggested Boeing was working on this kind of change for a while now.

Maybe that work was being planned for a later software drop, and when the "microprocessor issue" arose, they realized their best course of action was to accelerate the work.
Last edited by Revelation on Mon Aug 05, 2019 11:46 am, edited 1 time in total.
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seahawk
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 11:43 am

I do not see a reason to doubt Boeing, they gain nothing by a too optimistic schedule and they have the knowledge, resources and competence to even beat their own deadlines. Boeing always delivers.
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 11:44 am

Revelation wrote:
Yet the same media reports describing the design/architecture changes references Boeing sources saying they expect to submit their changes in September and hope for approval in October.


Which means either the scope of the changes reported is wrong, the reported timeline is wrong or the person giving the timeline information doesn't have a clue.


Revelation wrote:
Sure, it could be another overly optimistic date from Boeing, but the thing is, none of us know when the work on the design/architecture change started.


Imagine the furore there will be if it comes out that Boeing knew that not only was MCAS problematic, but the underlying FCS was also deficient and were working on solutions while (i) hiding MCAS and (ii) insisting the aircraft was safe!


Revelation wrote:
Some content posted around the time the "microprocessor issue" was first raised suggested Boeing was working on this kind of change for a while now.
Maybe that work was being planned for a later software drop, and when the "microprocessor issue" arose, they realized their best course of action was to accelerate the work.


No way would they undertake this kind of work for a regular update. Its far too large and carries significant risk in of itself.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 11:59 am

Amiga500 wrote:
Imagine the furore there will be if it comes out that Boeing knew that not only was MCAS problematic, but the underlying FCS was also deficient and were working on solutions while (i) hiding MCAS and (ii) insisting the aircraft was safe!

I don't know about you, but I haven't seen a meaningful piece of software that was not deficient to some degree or other.

As above I did work on two different efforts that were changes in architecture/design of the scope this one seems to be, or even bigger.

One of them was quite anticipatory, the technical leads sorted out most of the stuff ahead of time, the coding was relatively minor, the testing was really the long tent in the pole but it wasn't extraordinary.

The other was characterized by a bodged set of point fixes that took years to iron out.

Hopefully Boeing is doing the former rather than the later.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
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InsideMan
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 12:02 pm

seahawk wrote:
I do not see a reason to doubt Boeing, they gain nothing by a too optimistic schedule and they have the knowledge, resources and competence to even beat their own deadlines. Boeing always delivers.


Seriously? Boeing always delivers?

Thruth is, it is common business practice nowadays only to admit to what is impossible to deny anymore. Otherwise give out the thruth in very small and digestible bites. That way the stock price will suffer a lot less than as if they'd say right now "it won't fly again until 2020". Think of the frog and the boiling water....
 
planecane
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 12:15 pm

flyingphil wrote:
I have been wondering about this myself..

“346 People Have Died on Boeing’s Newest Jet. Why the Hell Does the CEO Still Have a Job?”
https://www.thedailybeast.com/why-the-h ... ax-scandal

A change in leadership is overdue at Boeing
https://www.theglobeandmail.com/busines ... at-boeing/



These articles could have been written by stitching together a lot of the posts in this thread (and its predecessors).

Regardless, they should at least get the facts correct. The first article blames Muilenburg for oversight of the MAX development when he wasn't on the commercial side until he became CEO (with responsibility for the whole company), which was less than a year before the first flight and many years past when the decisions were made that led to the necessity of MCAS.

The second article says that aerodynamics caused by the engine placement causes the "potential for the plane to stall during a climb" which is incorrect. That statement insinuates that there could be stalls during routine operations. The truth is that there is the potential for it to be easier to enter a stall during certain, very rare extreme maneuvers at the edge of the certified flight envelope.

Had Boeing just put the MCAS software in for the certification flights and then removed it before the model entered service, it is very likely that issue caused by the engine size and placement would have never led to a stall. The WSJ (I think) report detailed that the "old school" test pilot that wasn't happy that software would be used to solve the issue indicated that he was OK with MCAS because he felt that the situations where it would activate were so rare that it might never activate in service.
 
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 12:19 pm

Amiga500 wrote:
If that dual channel operation is not limited to MCAS alone, but instead is anything approaching the entirety of FCC capabilities, then airlines can completely forget about 2019 return to service. It'll be 12 months minimum from when the work started - they simply won't have enough people available that understand the architecture deeply enough to go any quicker and keep it safe. If significant chunks of the FCC OS and AS are being re-architected then I'm not even sure I'd see a 2020 return to service as realistic either.


boeing is building full FBW planes since decades
the 7x7 is all FBW
they dont need to invent the wheel for new

i really dont understand why such a world leading group like boeing didnt set up a big (!) team to adapt the 7x7 FBW concept on to the 737
at least after the first crash this would be a number one priority ,,.,.
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 12:23 pm

Revelation wrote:
I don't know about you, but I haven't seen a meaningful piece of software that was not deficient to some degree or other.


Code errors are a matter of course, and I know full well that aircraft and engines enter services with a raft of minor issues remaining - often remaining throughout service life unfixed - simply as they are instances which should never happen or are nuisance.

But, these are normally small detail issues. Not fundamental safety compromise issues.

Sitting on one is not equivalent to sitting on the other.


If Boeing knew that MCAS was dangerous and knew that the underlying FCS was also dangerous - and were working silently in the background to rectify both - how do they justify insisting the aircraft was safe to fly after Lion Air? [Hence why I cannot believe that they've been beavering away at this for months before the SHTF.]
Last edited by Amiga500 on Mon Aug 05, 2019 12:29 pm, edited 1 time in total.
 
Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 12:27 pm

asdf wrote:
i really dont understand why such a world leading group like boeing didnt set up a big (!) team to adapt the 7x7 FBW concept on to the 737
at least after the first crash this would be a number one priority ,,.,.


No no no - that'd mean essentially a new aircraft design.

Even worse would be trying to somehow rush a full FBW onto the MAX after Lion Air - it wouldn't be feasible. It'd be arguable whether it would cost Boeing less to just cancel the program and buy back the airframes already delivered than deal with the delays and issues trying to shoehorn a full FBW into 737 would cause!
 
StTim
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 12:58 pm

So they are going to check the the flying FCC against the standby one - and if there is a disagreement auto switch over? What if the standby FCC is the one that has developed a fault?
 
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sassiciai
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:07 pm

Revelation wrote:
Amiga500 wrote:
Imagine the furore there will be if it comes out that Boeing knew that not only was MCAS problematic, but the underlying FCS was also deficient and were working on solutions while (i) hiding MCAS and (ii) insisting the aircraft was safe!

I don't know about you, but I haven't seen a meaningful piece of software that was not deficient to some degree or other.

As above I did work on two different efforts that were changes in architecture/design of the scope this one seems to be, or even bigger.

One of them was quite anticipatory, the technical leads sorted out most of the stuff ahead of time, the coding was relatively minor, the testing was really the long tent in the pole but it wasn't extraordinary.

The other was characterized by a bodged set of point fixes that took years to iron out.

Hopefully Boeing is doing the former rather than the later.


Bolding above is mine!

Just a great example of a classic "coding error" that is actually quite difficult to spot! :P
 
Noshow
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:26 pm

Without MCAS the Pilots will have a raw flying MAX without "protection". If a 737 MAX is not FAA certifiyable without MCAS how can it be permitted to fly with MCAS disabled?
Couldn't we better take out the whole MCAS from the beginning please and let the pilots fly and trim themselves?
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:28 pm

Amiga500 wrote:
Revelation wrote:
I don't know about you, but I haven't seen a meaningful piece of software that was not deficient to some degree or other.

Code errors are a matter of course, and I know full well that aircraft and engines enter services with a raft of minor issues remaining - often remaining throughout service life unfixed - simply as they are instances which should never happen or are nuisance.

But, these are normally small detail issues. Not fundamental safety compromise issues.

Sitting on one is not equivalent to sitting on the other.

If Boeing knew that MCAS was dangerous and knew that the underlying FCS was also dangerous - and were working silently in the background to rectify both - how do they justify insisting the aircraft was safe to fly after Lion Air? [Hence why I cannot believe that they've been beavering away at this for months before the SHTF.]

I'm not trying to be adversarial, but am wondering why you make distinctions between classes of defects, then you lump MCAS (clearly a botched design and implementation) together with the FCC issue (not seen after 200M flight hours on 737NG, generated by toggling five bits all at the same time in locations chosen for the greatest impact rather than randomly, odds suggested to be on the order of one in ten trillion).

Obviously the former (MCAS) falls in to the 'must fix now' bucket as soon as its scope is understood, the later (FCC) could initially have fallen in to the bucket 'wait till next major release' and then the failed test moves it in to the 'must fix now' bucket.

As for the Watergate question (what did the CEO know, and when did he know it?), none of us know the answer, regardless of the disappearing AFP story. If the answer is the same as Watergate, so will be the response. Excessive greed is typically forgivable, cover ups / egregious dishonesty is not.
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:40 pm

sassiciai wrote:
Just a great example of a classic "coding error" that is actually quite difficult to spot! :P

Yes, indeed, that is the way that saying went in to my brain, and since then, it's a 'garbage in, garbage out' issue!
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Amiga500
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:43 pm

Revelation wrote:
I'm not trying to be adversarial, but am wondering why you make distinctions between classes of defects, then you lump MCAS (clearly a botched design and implementation) together with the FCC issue (not seen after 200M flight hours on 737NG, generated by toggling five bits all at the same time in locations chosen for the greatest impact rather than randomly, odds suggested to be on the order of one in ten trillion).

Obviously the former (MCAS) falls in to the 'must fix now' bucket as soon as its scope is understood, the later (FCC) could initially have fallen in to the bucket 'wait till next major release' and then the failed test moves it in to the 'must fix now' bucket.


If anything, it existing throughout the life of NG and Boeing quietly working on a fix prior to Lion Air but saying nothing makes perceptions worse, not better!

Anywayz, busy times in Seattle and I'm thankful I'm not working there right now.
 
SteelChair
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:44 pm

seahawk wrote:
I do not see a reason to doubt Boeing, they gain nothing by a too optimistic schedule and they have the knowledge, resources and competence to even beat their own deadlines. Boeing always delivers.


OMG I'm speechless. Delivers what? When? Does years late and billions over budget count?
 
Dieuwer
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:50 pm

Image

Read about "The monster of Seattle", how it killed hundreds of people and why it should NEVER ever be allowed to fly again.

https://www.spiegel.de/plus/boeing-737- ... de132096f8
 
Jetty
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:56 pm

:shock: Now the MAX has been labelled 'Killer plane' and 'Monster of Seattle' by 2 of the most prominent European news media in just a week. This must be the plane with the worst image in the history of aviation.

:tombstone:
Last edited by Jetty on Mon Aug 05, 2019 1:58 pm, edited 3 times in total.
 
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Revelation
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Re: Boeing 737MAX Grounded Worldwide Q3 2019

Mon Aug 05, 2019 1:57 pm

Amiga500 wrote:
If anything, it existing throughout the life of NG and Boeing quietly working on a fix prior to Lion Air but saying nothing makes perceptions worse, not better!

Yes, MCAS crossed a line for Boeing: Before MCAS, the automation did things at the request of the pilots. After MCAS, the automation made its own decisions and took its own actions. You would think this would have made them more cautious and introspective, but clearly it did not.

Amiga500 wrote:
Anywayz, busy times in Seattle and I'm thankful I'm not working there right now.

Agreed. Must be a real pressure cooker.
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Wake now, discover that you are the song that the morning brings
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